1. Field of the Invention
The present invention relates to a flap which applies elastic pressure to the tape which runs in a video tape cassette and its installing structure.
The flap is formed by coating both sides using a PET(Polyethylene Terephthalate) film as the base, with a composite containing a carbon black lubricant and a fitting method is adopted to install the flap.
2. Brief Description of the Prior Art
Generally, the flap which is applied to a video cassette tape is a thin elastic piece which is installed to prevent various problems caused when the tape runs loosely, by applying elastic pressure thereto.
It elastically supports the tape which runs between the flap and a pressing/supporting part on the other side of the flap and then over a tape guide roller. One side of the flap is attached to the front wall on the supply side of tape cassette about halfway down, and its other side is supported adjacent tape guide roller. Such a conventional flap(23) is formed by attaching at one end a two-sided adhesive tape(21), to one side of PET film (20), and a separate pressing/supporting tape (22) mixed with polyethylene (PE) and carbon black, or made of teflon, to the other end.
The flap formed in such a manner is fixedly attached to the front wall by using the said two-sided adhesive tape, as illustrated in FIG. 6.
The conventional flap formed in such a manner as described hereinbefore involves a problem in that it lowers productivity and thereby causes a rise in production costs, because 1) a separate pressing/supporting tape (22) must be formed with a grid-shaped or variously shaped embossed part on its outer face to prevent static electricity from being generated by friction, the shape face minimizing the area of contact with the video tape in the pressing/supporting part; and 2) the two-sided adhesive tape it uses is attached deviating from the correct position if a condition is changed only a little in the automatic production line. In such a case, the adhesive strength weakens, thereby causing the flap not to exercise its proper function in the case where it is used for a long time or under high-temperature conditions, even if it is attached to the correct position.
The Japanese Patent Journal Showa No. 55-14665 and the Japanese Utility Model Journals Showa No. 56-51185, No. 59-194184 and No. 62-106375 are known as prior art in which the fixing part on one side of the body of the tape cassette is extended and bent, or a fixing piece is made by stamping out a certain portion of the fixing part, and then a flap is installed by catching it in the fixing part, as a means to solve such a problem. These are not as good as expected for the reason that the fixed condition is not secure and the structure is complicated, and the life span is short even if the structure were simple.